SAP Professional Journal is publishing a 3 part FREE article series on ABAP coding named "An indider's guide to writing robust, undertandable, maintainable, state-of-the-art ABAP programs". This is a must read for ABAP newcommers and for already established ABAPers. For newcommers, ABAP stands for Advance Business Application Programming.
Part 1 - Fundamamental Rules and formal criteria
Part 2 - Best practices